FR3057345A1 - DEVICE FOR DRYING AND COOLING A GRANULAR PRODUCT BY ASCENDING AIR FLOW - Google Patents

Abstract

The invention relates to a column for drying and cooling (1) a granular product by ascending air flow against the current of a downward flow of the granular product, the column being divided in height to present: - a section low (10) cooling; - an upper section (12) of drying; - An intermediate section (11) intended to allow the descent of the granular product and to confine a flow of hot air in the upper section by preventing a cold air flow back in the upper section.

Description

The field of the invention is that of the design and manufacture of equipment for the food industry.

More specifically, the invention relates to a device for drying and cooling a granular product which has, for example, undergone heat treatment or cooking, or which has been obtained by extrusion.

In the field of the invention, the prior art provides a first device for drying and cooling a granular product. This device has two separate columns.

The granular product is intended to circulate inside these columns in a downward flow, against the flow of an upward air flow.

In a first column, the granular product is dried. Then, in a second column, the granular product is cooled. Each column thus has air injection means so as to circulate this air in an upward flow.

In these columns, there are retention organs which allow the granular product to be retained for a predetermined period of time at a precise height of the column, then to release it, so that it continues its journey inside the column. These retention members retain the product but nevertheless allow the upward air flow to pass through the organ and the granular product to be dried or cooled.

However, such a drying and cooling device has the drawback of being bulky. Indeed, this device requires a substantial space on the ground, due to the presence of two distinct elements.

According to another solution proposed by the prior art, there is known a device for drying and cooling a granular product which is less bulky than the solution described above. This drying and cooling device consists of a single column which has the two desired functions, namely the drying and cooling of a granular product.

This single column includes:

- a lower section which is intended to cool the product,

- a high section which is intended to dry the product.

This single column has a plurality of retention members which will allow the product to be retained at different heights in the column, so that the product can be dried and then cooled.

More specifically, the single column has in its lower section means which inject cold air which will rise inside the column by forming an ascending flow of cold air. We find in the upper section means that inject hot air. This hot air will then also go up in the column thus forming an upward flow of hot air.

This device for drying and cooling a granular product nevertheless has several drawbacks.

According to a first drawback, the action of the drying means is affected by the cooling means.

Indeed, the ascending cold air flow rises in the column and mixes with the ascending hot air flow. Consequently, compared to the first device proposed by the prior art, and at equal power, the upward flow of hot air is not as hot as it could be.

Also, the upper part of the column must support the flow of air expelled by means of hot air injection as well as that expelled by means of cold air injection. Consequently, the maximum flow rate of an air flow that the upper part can support cannot be devoted solely to the flow of hot air.

In addition, the meeting of the cold air flow and the hot air flow causes disturbances in the flow of the air flows having the consequence of not allowing a homogeneous cooling and / or drying of the granular product. .

According to another drawback, such a single column consumes much more energy in order to obtain a yield substantially comparable to that of the first solution proposed by the prior art (apart from the fact that, in the first solution, the product granular should be routed from the first column to the second column).

The invention particularly aims to overcome the drawbacks of the prior art.

More specifically, the invention aims to provide a device for drying and cooling a granular product which has a limited size and whose drying means are not affected by the means for cooling the granular product, compared to solutions proposed by the prior art.

The invention also aims to provide such a drying and cooling device which has an optimized energy balance.

Another object of the invention is to propose such a device which makes it possible to achieve uniform drying and cooling of a granular product.

These objectives, as well as others which will appear subsequently, are achieved by the invention which relates to a column for drying and cooling a granular product by an upward flow of air against a downward flow of the granular product, the column comprising:

- means for injecting hot air;

- means for injecting cold air;

- openwork retention members of the granular product, located at different heights of the column and intended to retain the granular product for a predetermined period of time then to release it, and to allow an upward flow of air to pass through it organ;

characterized in that it is divided in height to present:

- A lower cooling section including at least one perforated retention member and comprising the means for injecting cold air, and means for extracting cold air located at the upper end of the lower section;

- An upper drying section including at least one perforated retention member and comprising the means for injecting hot air, and means for extracting hot air located at the upper end of the upper section;

an intermediate section comprising means for transferring granular product from an overlying space to an underlying space, the transfer means having means for separating an air flow located in the underlying space of an air flow located in the overlying space, the intermediate section being intended to allow the descent of the granular product and to confine the flow of hot air in the upper section by preventing the flow of cold air from going up in the upper section.

The drying and cooling device according to the invention has a limited space due to its single column having a low cooling section and a high drying section.

Thanks to the invention, the drying and cooling of the granular product are separated and thus the means for cooling the granular product do not disturb the drying means of the granular product.

More specifically, the ascending cold air flow does not enter the upper drying section thanks to the separation means. As a result, the upward hot air flow is not, or at least minimally, disturbed by the upward cold air flow.

This confinement of the drying and cooling functions makes it possible to control the performance of the device and more specifically to achieve energy savings thanks to the efficiency of the device.

According to another advantage, the intermediate section serves as an intermediate space between the upper drying section and the lower cooling section. If the time spent by the granular product in this intermediate space is significant, bleeding of the dried granular product is possible.

According to an advantageous characteristic, the hot air injection means take the form of a rack having at least one lateral opening communicating with the outside of the column, the lateral opening being intended to be coupled to means of hot air supply, the locker including laminar distribution means.

By laminar distribution means is meant means which make it possible to distribute the flow of hot air uniformly in the column, at a precise height of this column, and which make it possible to generate a rise in the flow of hot air in the column in a laminar flow.

Such a laminar flow contributes to obtaining a homogeneous drying of the granular product.

According to another advantageous characteristic, the means for extracting the cold air take the form of a rack having at least one lateral opening communicating with the outside of the column, the lateral opening being intended to be coupled to means suction, the locker including laminar capture means.

The term “laminar capture means” means means which make it possible to draw in an upward flow of cold air at a precise height of this column, in a substantially homogeneous manner at any point of this height. This extraction of cold air by means of such laminar capture means contributes to the ascending cold air flow having a laminar flow.

According to a preferred embodiment, the compartments of the means for injecting hot air and means for extracting cold air are identical.

Such lockers offer an interesting modularity for implementing the means for injecting hot air and the means for extracting cold air.

Advantageously, each rack has two opposite lateral openings with respect to a central axis C of the column.

Thanks to these two lateral openings which are opposite with respect to a central axis C of the column, the suction of cold air and / or the injection of hot air tend to be carried out in a substantially homogeneous manner.

This homogeneity contributes to the formation of laminar flows of cold and hot air flows, these laminar flows promoting the obtaining of a homogeneous treatment for drying and cooling the granular product.

According to a preferred solution, the laminar distribution means and the laminar collection means of each bin take the form of a plurality of horizontal conduits parallel to each other, regularly distributed over the entire horizontal section of the bin, and having identical spacing. between each conduit, each conduit providing an air passage between the lateral opening (s) and the interior of the column.

Such a design of the distribution and collection means makes it possible to contribute to:

- ensure an essentially vertical laminar distribution of the hot air flow;

- avoid disturbing the flow of the cold air flow thus allowing it to be of an essentially laminar type.

Preferably, the conduits have a V-shaped section whose point is directed upwards.

This V-shaped section, the point of which is directed upwards, allows the granular product to flow over the walls of the V, and makes it possible to provide an air passage between the lateral opening (s) and the interior of the column thanks to the space inside the V.

In fact, the hot air brought through the side openings enters the hollow of the V, fills it, then emerges inside the column. Then, the spacing between each duct allows the hot air to rise inside the column and form a flow of hot air having an essentially laminar flow.

Advantageously, the conduits have a central narrowing, the space located between the central narrowing of two adjacent conduits forming an air and granular product passage.

Thanks to this central narrowing of each duct, the flow of the granular product through the crate is less disturbed. In addition, the supply of hot air and the suction from the side openings are distributed more evenly along the ducts.

According to a first preferred variant of embodiment, the transfer means and the separation means are grouped within an isolation airlock, the lower section comprising at its upper end means for homogeneous distribution of the granular product coming from the airlock. 'insulation.

Thanks to this design, the containment of air flows in the upper and lower sections is particularly optimized. Indeed, such an airlock prevents any rise in an air flow due to the continued existence of a physical separation between the low section and the high section.

Advantageously, the isolation airlock takes the form of a rotary airlock (this rotary airlock can, more precisely and for example, be a "rotary lock" or even a "cellular airlock").

The homogeneous distribution means make it possible to distribute the dried granular product fairly inside the lower section, following the grouping of the product which is inherent in the operation of an isolation airlock.

According to a second preferred embodiment, the transfer means and the separation means comprise at least one confining retention member intended to retain the granular product for a predetermined period of time and then to release it, the confining retention member being movable between at least one position for releasing the granular product, and a retention position in which it forms an essentially airtight partition intended to confine the flow of hot air in the upper section by preventing the flow of cold air from go back to the upper section.

Thanks to this design, the intermediate section can be produced with elements in common with the upper and lower sections of the drying and cooling column according to the invention.

In this alternative embodiment, the ascending cold air flow does not enter the upper drying section thanks to the confining retention member which forms a partition which is essentially airtight when it is in a retention position of the granular product.

In addition, the confining retention member makes it possible to retain the dried granular product for a predetermined period of time. During this period of time, the radiation of the hot air inlet by the hot air injection means makes it possible to advantageously contribute to the bleeding of the product before it cools.

According to a preferred embodiment, the perforated retention members and the confining retention member each have a plurality of supports extending over the entire horizontal section of the crate, the supports being capable of retaining the granular product when the retention members are in a retention position, each support being integral with a horizontal axis rotatably mounted, the axes being coupled together and with a motor by means of a connecting rod, the motor being able to rotate the axes so to retain or release the granular product.

There is thus a unique overall design of the confining retention member and of the openwork retention members. Indeed, between each application only the supports then take a different form.

Advantageously, the motor is of the oscillating movement type so that the granular product is released alternately on each side of the axes.

Such a motor with oscillating movements optimizes the distribution of the granular product when it descends along the column. This oscillatory movement is more specifically programmed to have a movement to the left and a movement to the right at an identical angle and speed.

Indeed, in the prior art the retention members can take the form of a valve. These valves are movable in rotation about an axis positioned at one end of the valves. Consequently, these valves produce the same tilting movement each time, which tends to push back the granular product on one side of the column.

According to a preferred characteristic, each support of an openwork retention member is formed by bars having a triangular cross section, the bars being spaced from each other so as to provide an air passage while preventing the passage of granular product. .

Such bars with a triangular cross section make it possible to optimize the passage of the air flow through the organ, while retaining the granular product.

According to another preferred characteristic, each support of a confining retention member is formed by a solid surface, all of the supports of a confining retention member forming, in the retention position, the partition essentially airtight.

Such a support formed by a solid surface makes it possible to form a partition which is essentially airtight in a simple and economical manner.

According to an advantageous solution, the drying and cooling column consists of stackable elements including:

- the means for injecting hot air;

- means for injecting cold air;

- the means of extracting cold air;

- openwork retention organs.

Such stackable elements give an interesting modularity to the drying and cooling device according to the invention. Indeed, the column can thus be modified by the addition of new elements, the reorganization of existing elements and / or the removal of elements already in place.

This modularity makes it easy to modify the type of granular product that the column according to the invention is intended to treat.

Also, this design simplifies the installation and uninstallation of a column according to the invention. For example, in a factory that does not have access adapted to receive a monobloc column, then the column according to the invention can advantageously be assembled directly on site, following the delivery of the column, piece by piece, directly to the core From the factory.

In the case where the column according to the invention comprises a confining retention member, then the latter can be included in the stackable elements.

Preferably, the stackable elements include spacing units intended to be stacked on top of:

- the means for injecting hot air;

- means for injecting cold air;

- the means of extracting cold air;

- the openwork retention members, the spacing units comprising a detector for the presence of the granular product, the detector being capable of causing the activation of one or more components of the column.

These spacing units further increase the modularity offered by the drying and cooling column according to the invention.

In addition, the granular product presence detector, being capable of causing the activation of one or more components in the column during the detection of the presence of granular product inside the spacing units, allows as a result to achieve energy savings.

Indeed, for example, an openwork retention member underlying a spacing unit provided with a presence detector can be configured to enter into operation only from the moment when the granular product is effectively retained on its surface.

Thus, an operation consuming electricity may be limited when the granular product is not present.

Of course, in the presence of a confining retention member, one or more spacing units can be stacked above this member.

According to an advantageous characteristic, each spacing unit comprises means for visualizing the interior of the spacing unit and means for withdrawing the granular product inside the spacing unit.

According to another advantageous characteristic, each spacing unit comprises means for probing the temperature of the granular product inside the spacing unit.

Spacing units provided with such display means and / or sampling means and / or temperature probing means make it possible to adjust the drying and cooling parameters of the drying and cooling column according to the invention.

According to a preferred embodiment, the intermediate section consists of a spacing unit and of a confining retention member, the spacing unit being situated above the confining retention member, and the hot air injection means are located at the lower end of the upper section.

Such a design of the intermediate section makes it possible to optimize the bleeding of the granular product before it is cooled.

Advantageously, the means for extracting the hot air comprise suction sockets situated above the column, the suction sockets being regularly distributed around a central axis C of the column.

Such suction points located above the column, regularly distributed around a central axis C of the column, make it possible to avoid or limit, the appearance of disturbances in the upward hot air flow, this which would disturb the drying of the granular product.

According to a preferred embodiment, the drying and cooling column comprises means for supplying granular product comprising a chute mounted to rotate about a central axis C of the column, the chute having an eccentric ejection end capable of describe a horizontal circle in the column.

Such means for supplying granular products make it possible to optimize the arrival of the granular product inside the column by distributing it homogeneously inside said column and in particular homogeneously on the first retention member. openwork. Such a chute is also of paramount importance in avoiding harmful turbulence in the upward laminar hot air flow.

Advantageously, the chute has an inverted cone on the ejection end.

Such an inverted cone makes it possible to optimize the homogeneous diffusion of the granular product over the largest possible surface of the openwork retention member.

According to an advantageous characteristic, the drying and cooling column comprises an equalization rake coupled with the chute mounted rotatably, the equalization rake being mounted movable in height.

The leveling rake allows you to adjust the layer height of the granular product to be treated. This leveling rake also avoids solidification of the product, especially if the granular product to be treated tends to stick.

Other characteristics and advantages of the invention will appear more clearly on reading the following description of preferred embodiments of the invention, given by way of illustrative and nonlimiting examples, and of the appended drawings among which:

- Figure 1 is a schematic representation of a first embodiment of a drying and cooling column according to the invention

- Figure 2 is a schematic representation of a second embodiment of a drying and cooling column according to the invention;

- Figure 3 is a schematic representation according to a perspective view of the upper end of a drying and cooling column according to the invention;

- Figure 4a is a schematic representation along a cross section of the upper end of a drying and cooling column according to the invention, illustrating the chute and the rotary equalizing rake;

- Figures 4b and 4c illustrate the operation of an embodiment of the equalization rake;

- Figure 5 is a schematic representation of a spacing unit of a drying and cooling column according to the invention;

FIGS. 6 and 7 are schematic representations according to a perspective view and a cross section of a rack of means for injecting hot air or means for extracting cold air from a drying column and cooling according to the invention;

- Figure 8 is a schematic representation according to a top view of an openwork retention member or a confining retention member of a drying and cooling column according to the invention;

- Figures 9a, 9b and 9c are schematic representations along a cross section of a retention member of a drying and cooling column according to the invention, respectively in a retention position of the granular product and in two positions of release of the granular product;

- Figures 10 to 12 are schematic representations of a support and its axis, respectively in a side view, a top view and a cross section;

- Figures 13 and 14 are partial schematic representations of a retention member of a drying and cooling column according to the invention;

- Figure 15 is a schematic illustration of a cross section of bars of an openwork retention member of a drying and cooling column according to the invention.

As can be seen in Figures 1 and 2, the device according to the invention corresponds to a drying and cooling column 1. This column allows first to dry and then cool a granular product by the intermediate of ascending air flows which circulate against a descending flow of granular product.

More precisely, the granular product is introduced inside the column from the top, it circulates inside the column by simple gravity, then it arrives, dried and cooled, at the bottom of the column in a drain hopper. who collects the product.

The particularity of the drying and cooling column 1 is that it is divided in height so as to present:

- A lower cooling section 10;

- an intermediate section 11;

- a high drying section 12.

Consequently, the granular product circulates inside the column, passing first through the upper drying section, in which the product is dried, then through the intermediate section, and finally into the lower cooling section where the product is cooled.

According to the present embodiment, the upper drying section 12 includes three perforated retention members 3 of the granular product, which are located at different heights of the column.

The openwork retention members 3 of the granular product are intended:

- to retain the granular product for a predetermined period of time and then to release it;

- to allow an ascending air flow to pass through the organ, including and above all in the retention position.

The upper drying section 12 also includes:

- Hot air injection means 20, located at the lower end of the upper section;

- means for extracting the hot air 50, located at the upper end of the upper section.

As can be seen in Figures 1 and 2, the openwork retention members are spaced from each other.

The upper drying section is thus delimited in its lower part by the hot air injection means and in its upper part by the hot air extraction means.

The intermediate section includes means for transferring granular product from an overlying space in the intermediate section (the upper section) to a space underlying the intermediate section (the lower section). These transfer means also have means for separating an air flow located in the underlying space from an air flow located in the overlying space. This intermediate section thus allows the descent of the granular product from the upper section to the lower section, while confining the flows of hot air in the upper section while also preventing the flow of cold air located in the lower section from going up into the high section.

According to a first alternative embodiment illustrated in FIG. 1, the transfer means and the separation means comprise a confining retention member 4.

The confining retention member is intended to retain the granular product for a predetermined period of time and then to release it.

This confining retention member is movable between at least one position for releasing the granular product and one position for retaining the granular product.

In its granular product retention position, the confining retention member forms an essentially airtight partition. As will be detailed later, this partition is intended to confine the flow of hot air in the upper section by preventing a flow of cold air from going up in this upper section.

According to a second alternative embodiment illustrated in FIG. 2, the transfer means and the separation means are grouped together in an isolation lock 110. In this case, the lower section comprises at its upper end distribution means homogeneous granular product from the isolation airlock.

According to the present embodiment, the isolation airlock is a rotary airlock, for example of the rotary lock type or even of the cellular airlock type.

With reference to FIGS. 1 and 2, the lower cooling section 10, for its part, comprises:

- an openwork retention member 3;

- means for injecting cold air 21;

- means for extracting cold air 51.

As can be seen in Figures 1 and 2, the lower section is delimited in its lower part by the cold air injection means 21 (and the drain hopper) and in its upper part by the means for extracting cold air 51.

The openwork retention member 3 of this lower section thus makes it possible to retain the granular product for a predetermined period of time in this lower section so that it is traversed by an ascending flow of cold air.

As can be understood in the context of the first embodiment illustrated in FIG. 1, the means for extracting cold air 51, and the confining retention member 4, which overhangs the means of extraction of cold air, help to confine the cold air flow in the lower cooling section to prevent this cold air flow from going up in the upper sections by disturbing the hot air flow.

According to the present embodiment, the drying and cooling column 1 is made up of stackable elements.

These stackable items include:

- The hot air injection means 20;

- The cold air injection means 21;

- The means for extracting cold air 51;

- the openwork retention members 3;

- the confining retention member 4 (of the intermediate section, in the context of the first alternative embodiment illustrated in FIG. 1).

The stackable elements also include spacing units 7 which are intended to be stacked above the hot air injection means, cold air injection means, cold air extraction means , openwork retention members, and the confining retention member.

As can be seen in Figure 5, a spacing unit 7 forms a column section. This spacing unit thus makes it possible to contain the granular product above one of the means or of one of the organs mentioned above.

Figures 3 4a, 4b and 4c illustrate embodiments of an upper part of an upper section 12 for drying a drying and cooling column 1 according to the invention. According to these embodiments, there is a supply box 120 stacked on a spacing unit 7.

The supply box 120 comprises means 8 for supplying granular products.

These means for supplying granular products comprise a chute 80 rotatably mounted about a central axis C of the column. The chute presents:

- one end coupled on the upper face of the column, on the central axis C, this end being intended to receive the granular product which must be injected into the column;

- an eccentric ejection end 81.

The end coupled on the upper face can be rotated by means of an upper motor 83. When the chute is rotated, the eccentric ejection end describes a horizontal circle in the column.

As can be seen, the chute 80 has an inverted cone 82 on its ejection end 81. This inverted cone makes it possible to increase the radius of dispersion of the granular product when it is ejected from the chute.

It can be seen in Figures 2 and 4a that the cooling drying column according to the invention comprises an equalization rake 9. This equalization rake is coupled with the chute 80 which is rotatably mounted. As a result, the leveling rake also rotates inside the column.

In a complementary manner, the leveling rake is mounted displaceable in height (displacement illustrated by FIG. 2 in which the rake is represented at two different heights: a high PH position and a low PB position). This leveling rake takes place inside the spacing unit 7 underlying the feed box 120. This leveling rake thus makes it possible to equalize the surface of the granular product ejected by the chute.

With reference to FIGS. 4a to 4c, the leveling rake 9 carries underlying pallets 92. These pallets are intended to equalize the surface of the granular product. These palettes are:

- adjustable in rotation around a vertical axis parallel to the central axis C of the column;

- adjustable in height.

Preferably, the pallets located near the central axis C of the column are lowered relative to the other pallets to improve the leveling of the surface of the granular product.

The chute can also be adjusted in height. In this way, it is preferably adjusted to come almost into contact with the top of the layer of granular product to deposit the granular product as close as possible to this layer, without dispersing it in an uncontrolled manner. In this way, the distribution of the granular product is better controlled, which makes it possible to optimize the drying and cooling of the granular product in the column.

Figures 4b and 4c illustrate the action of an equalization rake according to a particular embodiment. According to this design, the leveling rake 9 is provided with extension arms 90 located at its ends. These extension arms are located in the same plane of rotation as the leveling rake and make it possible to optimize the leveling of the granular product. To optimize this equalization, the extension arms are more precisely coupled mobile in rotation at the ends of the equalization rake, while also being provided with return means 91 in a deployed position. Thus, as can be seen in FIGS. 4b and 4c, the extension arms cooperate with the wall of the spacing unit as the equalization rake rotates. In contact with the wall, they fold back, while they are deployed in space near the corners of the box. These extension arms thus make it possible to equalize the height of granulated product on areas which the leveling rake cannot reach.

The return means 91 are constituted by return springs. According to an embodiment not shown, pneumatic cylinders are also coupled to the extension arm to absorb the return movement and prevent the extension arms from violently striking the wall.

The ends of the extension arms may have means of cooperation with the wall to reduce the friction exerted on this wall. These cooperation means can take the form of rollers or Teflon rubbers.

The supply box 120 has the means for extracting the hot air 50. These means for extracting the hot air 50 more precisely take the form of suction inlets 500 located above the column. These suction intakes are regularly distributed around a central axis C of the column and thus make it possible to avoid the appearance of turbulence in the lime air flow, which is for example the case when an air flow hot rising is sucked by suction nozzles located on the side wall of a column. In this case, as can be seen in Figure 1, there are two aspirations and are distributed on either side of the central axis C.

Preferably, to optimize the air flows, the supply box has a ratio of approximately 1.4 between the height and the width of the box.

As explained above and according to FIG. 2, the second alternative embodiment of the transfer means and separation means also has the particularity of having means for homogeneous distribution of the granular product coming from the isolation airlock. These homogeneous distribution means are located at the upper end of the lower section and take the form of a supply box as described above.

Thanks to this second supply box, we find the same capacities for homogeneous distribution of the granular product at the outlet of the airlock (which groups the granular product), and for extracting the air flow. This second supply box also includes an equalization rake and a chute identical to those described above.

Economies of scale can be achieved by using two identical power boxes.

According to the same principle, the column illustrated in FIG. 1 comprises two hoppers 1220, 1021 for recovering the granular product in which the hot air injection means 20 and the cold air injection means 21 are integrated.

As explained above and as can be seen in FIG. 5, a spacing unit 7 takes the form of a box constituting a horizontal part of the drying and cooling column according to the invention.

As can be seen in FIGS. 3 and 5, the spacing unit comprises display means 71 from the interior of the spacing unit 7.

The spacing unit also comprises, a presence detector (not illustrated) of the granular product, means for sampling the granular product located inside said spacing unit, and means for probing the temperature (not illustrated) of the granular product located inside said spacing unit.

The presence detector of the granular product is likely to cause the activation of one or more components of the column.

More specifically, the presence detector of the spacing unit allows the activation of an openwork or confining retention member located directly below the spacing unit concerned. Such a presence detector makes it possible to avoid the operation of a retention member when there is no granular product to be treated.

According to the embodiment illustrated in FIGS. 1, 6 and 7, the hot air injection means 20 are integrated into a rack 22.

It can be observed that the means for extracting cold air 51 are also integrated into a rack 22.

The lockers 22 are identical for the means for injecting hot air and for the means for extracting cold air.

These lockers 22 have two lateral openings 220 which communicate with the outside of the column. A lateral opening is intended to be coupled with means for supplying hot air or with suction means, depending on whether the rack is intended to constitute means for injecting hot air or means for extracting the 'cold air. The rack also includes means for laminar distribution of the hot air flow and means for laminar collection of the cold air flow.

As can be seen in Figures 1 and 6, the two side openings 220 are opposite one another with respect to a central axis C of the column.

According to this embodiment illustrated in Figures 6 and 7, the laminar distribution means and the laminar sensing means of each bin 22 take the form of a plurality of conduits 221, horizontal and parallel to each other. These conduits make it possible to provide an air passage between the lateral openings 220 and the interior of the column.

These conduits 221 are regularly distributed over the entire horizontal section of the rack. These conduits also have identical spacing between each conduit.

More specifically, as can be seen in Figures 6 and 7, the conduits have a V-shaped section whose tip is directed upwards. The conduits thus have two flaps 2210 forming the tip of the V. These flaps are intended to distribute on each side of the conduit the granular product during its fall.

The conduits have an inverted V-shaped section.

Each pan 2210 more specifically has a lower fold 2211 making it possible to prevent the granular product from being sucked in when the rack is part of the means for extracting cold air.

As can be seen in Figure 6, the conduits 221 have a central narrowing, the space between the central narrowing of two adjacent conduits forming a passage for both the air and the granular product.

Such central narrowing makes it possible to contribute to the laminar distribution and to the laminar capture of the hot and cold air flows. Indeed, a central narrowing makes it possible to increase the flow of air sucked or expelled from below the inverted V near the central part of a duct, compared to the flow of air sucked or expelled near the ends of the conduits located near the side openings.

As can be seen in Figures 1 and 8, the openwork retention members 3 and the confining retention member 4 have common design elements.

More specifically, according to Figure 8, the perforated retention members 3 and the confining retention member 4 each have a plurality of supports 6 which extend over the entire horizontal section of the crate. These supports make it possible to retain the granular product when the retention members are in a retention position. These supports therefore take a different form depending on the retention member which is either of the openwork type or of the confining type.

As can be seen in Figures 8 to 14, each support 6 is secured to a horizontal axis 61.

More precisely, as illustrated by FIGS. 8, 9a, 9b and 9c, the horizontal axes 61 are rotatably mounted and are coupled together and with a motor 63 by means of a connecting rod 62. The motor thus makes it possible to '' rotate the axes so as to retain or release the granular product. More precisely, as can be seen in FIGS. 9a to 9c, the motor is of the oscillatory movement type so that the granular product can be released alternately on each side of the axes 61.

As illustrated in FIG. 9a, the supports are in a position for retaining the granular product. The supports then form a flat surface.

Figures 10 to 13 illustrate a support 6 carried by an axis 61. The support is notably coupled to an axis 61 by means of reinforcements 64. These reinforcements 64 comprise a plurality of triangular plates 641 regularly distributed along the axis and coupled to each other by a tensioning element 640.

This design of the support improves its rigidity.

As illustrated in FIG. 13, it can be observed that a confining or perforated retention member has flanges 602 making the connection between a support near a side wall 600 of the retention member and a support 6 in retention position. These flanges 602 are adapted to an oscillatory movement of the axes and of the supports, and this in particular by creating a clearance between the side wall and the support located near this side wall. These flanges 602 are also inclined so as to prevent the granular product from being blocked between the side wall and a support.

According to the present embodiment illustrated in FIG. 14, for a retention member to be an openwork retention member 3, each support 6 then takes the form of bars 60. These bars are parallel to each other and are regularly spaced from each other.

As can be seen in Figure 15, these bars 60 have a triangular cross section with an upper face arranged flat to retain the granular product. These bars are spaced from each other so as to provide an air passage while preventing the passage of granular product. Such bars of triangular cross section make it possible to optimize the passage of air, and in particular allow air perforation of the order of 50%, which limits the pressure losses while homogenizing the passage of the air.

In the context of a confining retention member 4, each support is then formed by a solid surface. The set of supports of a confining retention member then forms, in the retention position, a partition which is essentially airtight, the supports then being edge to edge.

In addition, the column is formed by a double insulating wall. This characteristic is illustrated in FIG. 13 in which there is a wall 600 having an insulating space 601, the insulating space being able to be filled with an insulating material. The supply box 120 illustrated in FIG. 3 is more specifically provided with the double insulating wall so as to avoid a phenomenon of condensation inside the column.

Preferably, the column wall and the materials intended to come into contact with the granular product are made of food-grade stainless steel.

The column can also include energy recovery means which notably consist in recycling the cold air flow and the hot air flow to reinject them into the column.

Claims (8)

1. Column for drying and cooling (1) of a granular product by upward air flow against the flow of a downward flow of the granular product, the column comprising: - means for injecting hot air (20); - means for injecting cold air (21); - openwork retention members (3) of the granular product, located at different heights of the column and intended to retain the granular product for a predetermined period of time then to release it, and to allow an upward flow of air to pass through of the organ; characterized in that it is divided in height to present: - a lower cooling section (10) including at least one perforated retention member and comprising the means for injecting cold air, and means for extracting cold air (51) located at the upper end of the lower section; - an upper drying section (12) including at least one perforated retention member and comprising the means for injecting hot air, and means for extracting hot air (50) located at the upper end of the upper section; - An intermediate section (11) comprising means for transferring granular product from an overlying space to an underlying space, the transfer means having means for separating an air flow located in the space underlying an air flow located in the overlying space, the intermediate section being intended to allow the descent of the granular product and to confine the flow of hot air in the upper section by preventing the flow of cold air go up in the upper section. 2. drying and cooling column (1) according to claim 1, characterized in that the hot air injection means (20) take the form of a rack (22) having at least one lateral opening (220 ) communicating with the outside of the column, the lateral opening 5 being intended to be coupled to means for supplying hot air, the rack including laminar distribution means. 3. Drying and cooling column (1) according to any one of the preceding claims, characterized in that the means 10 cold air extraction (51) take the form of a rack (22) having at least one side opening (220) communicating with the outside of the column, the side opening being intended to be coupled to suction means, the rack including laminar capture means. 4. drying and cooling column (1) according to claims 2 and 3, characterized in that the compartments (22) means for injecting hot air (20) and means for extracting cold air (51) are identical. 5. drying and cooling column (1) according to claim 4, characterized in that the laminar distribution means and the laminar collection means of each rack (22) take the form of a plurality of horizontal conduits (221) parallel to each other 25 others, regularly distributed over the entire horizontal section of the rack, and having an identical spacing between each duct, each duct providing an air passage between the lateral opening (s) (220) and the interior of the column. 30 6. Drying and cooling column (1) according to any one of the preceding claims, characterized in that the transfer means and the separation means are grouped together in an isolation lock (110), the lower section (10) comprising at its upper end means for homogeneous distribution of the granular product coming from the isolation airlock. Drying and cooling column (1) according to any one of Claims 1 to 5, characterized in that the transfer means and the separation means comprise at least one confining retention member (4) intended to retain the granular product for a predetermined period of time and then releasing it, the confining retention member being movable between at least one position for releasing the granular product, and a retention position in which it forms an essentially airtight partition intended to contain the hot air flow in the upper section by preventing the cold air flow from going up in the upper section. Drying and cooling column (1) according to claim 7, characterized in that the perforated retention members (3) and the confining retention member (4) each have a plurality of supports (6) extending mainly over the horizontal section of the rack, the supports being able to retain the granular product when the retention members are in a retention position, each support being integral with a horizontal axis (61) mounted to rotate, the axes being coupled together and with a motor (63) by means of a connecting rod (62), the motor being able to drive the axes in rotation so as to retain or release the granular product. Drying and cooling column (1) according to any one of the preceding claims, characterized in that it consists of stackable elements including: - the means for injecting hot air (20); - the means for injecting cold air (21); - the means for extracting cold air (51); - the openwork retention members (3). 10. drying and cooling column (1) according to the preceding claim, characterized in that the stackable elements 5 include spacing units (7) intended to be stacked above: - the means for injecting hot air (20); - the means for injecting cold air (21); - the means for extracting cold air (51); 10 - the openwork retention members (3), the spacing units comprising a detector for the presence of the granular product, the detector being capable of causing the activation of one or more components of the column. 11. Drying and cooling column (1) according to any one of the preceding claims, characterized in that it comprises means (8) for supplying granular product comprising a chute (80) rotatably mounted around a central axis C of the column, the chute having an eccentric ejection end (81) capable 20 to describe a horizontal circle in the column. 2211